Less than two months later, the state decided to get rid of those standards.
That decision came after the giant for-profit hospital chain made contributions to Republican Gov. Rick Scott and his party that dwarfed those the company made to candidates or parties in other states.
"The whole situation is outrageous. It's just outrageous," said Louis St. Petery, a pediatric cardiologist in Tallahassee and former executive vice president of the Florida chapter of the American Academy of Pediatrics.
Doctors from around the state say the decision came right from the governor's office. Representatives for Tenet and Scott deny conversations took place between them about getting rid of the standards.
'Poor public policy and poor politics'
In the fall, cardiac doctors implored the state of Florida to keep the hospital standards. The doctors argued that the quality standards have been in place since 1977, saved children's lives and had become a model for other states.
When the standards were dropped anyway, the parents of four children with heart defects took the state to court.
Florida's Department of Health said the quality standards had to go because the Legislature had never given permission to put them in place.
The standards have been in place and uncontested for 38 years.
"Our number one priority is the health of all Floridians, especially children," Department of Health spokeswoman Mara Gambineri said in an email to CNN.
"We fully support best practices and high standards of care at Florida's hospitals. As an executive branch agency, the department's authority is limited to those functions statutorily delegated by the Legislature."
Pediatric heart experts appointed by the state to look out for children with heart defects took exception.
At a hearing, Dr. William Blanchard, a pediatric cardiologist and former medical director of the Nemours Children's Clinic in Pensacola, said getting rid of the standards is "both poor public policy and poor politics."
Dr. Jeffrey Jacobs, a professor of surgery at Johns Hopkins, argued that the standards "are necessary to protect the vulnerable children with heart disease."
'It is the failure of an entire team and system'
In 2014, Jacobs headed up the review by the state's expert panel
that showed many vital tests and services for children's hearts were lacking at St. Mary's Medical Center in West Palm Beach. He wrote that the Tenet-owned hospital was not able to maintain proficiency in heart operations on children.
"It is the failure of an entire team and system," wrote Jacobs, chairman of the Society of Thoracic Surgeons National Database Workforce.
Jacobs recommended the hospital stop performing heart surgery on babies younger than 6 months.
Legally, the hospital could ignore his suggestion -- and it did.
The state did not step in.
Babies continued to die
at St. Mary's.
And, after CNN's investigation, the state rushed to the hospital's defense.
Within days, Department of Health spokeswoman Tiffany Cowie told reporters that state data
showed St. Mary's mortality rate wasn't nearly as high as CNN had found.
But Cowie didn't mention a crucial detail: The state data she referred to didn't take into account half of the babies' deaths.
Those babies had surgery at St. Mary's, but when their health spiraled downward, they were transferred to other hospitals. Those hospitals could not save them.
The database Florida uses did not include those deaths
, according to experts who manage that database.
Even though the state defended St. Mary's mortality rate, in August the hospital closed its pediatric heart surgery program
and the CEO resigned.
Pediatric heart doctors were relieved. But they weren't prepared for what was ahead.
'A little hard to swallow'
In July, the state announced it would repeal hospital standards for children's heart surgery.
Doctors who care for children with congenital heart disease say they're suspicious about the timing, about two months after CNN's report showing St. Mary's failed to meet those state standards.
David Nykanen, a pediatric cardiologist and member of the state's Cardiac Technical Advisory Panel
, points out that Scott has been in office since 2011, and his administration never objected to the standards until a Tenet hospital was found publicly not to meet them.
"The coincidence is just a little too much," said Nykanen, co-director of the Heart Center at Arnold Palmer Hospital for Children in Orlando. "It's just a little hard to swallow."
In an email to CNN, Scott's spokeswoman, Jeri Bustamante, said that to her knowledge, Tenet did not have conversations with the governor or anyone on his staff about the pediatric heart surgery standards.
A spokeswoman for Tenet concurred.
"At no time have we discussed the pediatric cardiac standards with the governor or his office, or with any elected official or anyone on their staff," Tenet's Shelly Weiss Friedberg wrote in an email to CNN. "Our opinion was not sought on the standards nor have we expressed a position on the possible repeal of the standards or the role of the Cardiac Technical Advisory Panel."
While doctors interviewed for this article say they can't show a quid pro quo, they note Tenet's sizable contributions to Scott's campaigns in the two years preceding his administration's decision to get rid of standards that a Tenet hospital did not meet.
In 2013 and 2014, Tenet contributed $50,000 each year to Let's Get to Work
, Scott's political action committee. The next largest Tenet contribution those years to a state candidate's PAC was $25,000.
Each of those two years, Tenet also contributed $50,000 to the Republican Party of Florida, which dominates the state Legislature. The next largest Tenet contribution those years to a state political party was $20,000 to the Democratic Party in Illinois.
CNN's analysis of Tenet's contributions was confirmed by the National Institute of Money in State Politics
, a nonprofit, nonpartisan group that tracks campaign contributions.
"When a big organization like Tenet gives money, they expect access. They expect the politicians to give them everything they want," said Dr. Ira Gessner, professor emeritus of pediatric cardiology at the University of Florida College of Medicine and an advisory member of the state's Cardiac Technical Advisory Panel.
"If someone is contributing at that level, obviously they have to have some influence," said Nykanen, a member of the Food and Drug Administration's Pediatric Advisory Committee. "If Tenet Healthcare contributed so much money, you'd think they have the ear of the governor and the politicians."
Doctors outside the state said they were surprised that Florida would move to repeal its own safety standards for children.
"I can't think of anywhere else in the country where you have safety standards and someone doesn't like them, so you just have it repealed," said Dr. Peter Pronovost, senior vice president for patient safety and quality at Johns Hopkins Medicine.
"These standards have been in use for more than 30 years, and they're widely acknowledged to ensure safety -- why would you repeal them? If the state really felt it didn't have the legislative authority to have the standards, why wouldn't they go out and get that authority?"
A spokeswoman for the Florida Department of Health did not explain why the state didn't seek legislative authority for the standards.
An internationally renowned cardiac expert agreed that the standards are necessary.
"If we abandon medical standards, we create a free-for-all system in which any hospital or provider can perform any procedure without regard to the qualifications of the medical staff or capabilities of the program," said Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic.
Abandoning standards, he said, "puts the most vulnerable and precious patients at unacceptable risk."
Cutting off discussion
Children's heart doctors in Florida say they believe the directive to get rid of the standards came straight from Scott's office.
But they say Scott's defense of the Tenet hospital started even earlier.
A doctor who asked not to be named because he feared state retribution said that in 2014, a high-ranking state official asked that the situation at St. Mary's not be discussed at a meeting of the state's Cardiac Technical Advisory Panel.
"She wanted to cut off any discussion of St. Mary's -- to take it off the agenda," he said. "I told her that was ridiculous, that the agenda had already been sent out."
The physician said, "I asked why she wanted St. Mary's off the agenda, and she said she had gotten orders from the surgeon general's office."
Members of the Cardiac Technical Advisory Panel said that after the panel wrote a scathing review of the pediatric heart surgery program at St. Mary's, the state asked to start editing their reviews.
"We told them no way," said one of the physicians, who also asked not to be named for fear of state retribution.
Then, the doctors said, those state officials suggested that hospital reviews shouldn't be in writing at all -- the doctors should instead give oral reports on what they had found.
"We were startled," said Blanchard, a member of the panel. "It was a system that had worked well for umpteen years."
Then Jennifer Tschetter, the Department of Health's chief of staff at the time and now its chief operating officer, said the state intended to repeal the standards, the doctors said.
The doctors said they were surprised as Tschetter had been supportive of the standards for years.
"We all felt like the directive came from much higher," said Blanchard, the statewide pediatric cardiology consultant for Florida's Children's Medical Services, a part of the Department of Health.
At a meeting, state officials said the decision came from the surgeon general, Blanchard said.
"He's Scott's appointee," Blanchard said. "So I assume this came from the governor, and if (state employees) didn't follow through on that directive, their jobs were in jeopardy."
Gessner, the cardiologist at the University of Florida, said in his experience, important decisions at the Department of Health come from the governor's office.
"I can't believe this came from anyone less than the governor," he said. "I think his message was clear: Get rid of the standards."
Nykanen, the cardiologist in Orlando, agrees.
"(Tschetter) was always very careful at every meeting to say there's no political agenda here, but we thought to ourselves, 'Do you think we're stupid?' " he said.
Ruling in the state's favor
In December, a judge ruled in the state's favor
and said the standards for pediatric heart hospitals could be taken off the books.
Florida Administrative Law Judge John Van Laningham didn't base his ruling on the state's argument that it lacked the legislative authority to enact the standards.
Instead, he said the parents who took the state to court had failed to prove that getting rid of the standards would lower the quality of their children's care.
The judge wrote that the notion that hospitals "would suddenly stop providing quality pediatric cardiac services immediately upon repeal of the Standards rests on pure speculation -- and is a little insulting to the health care professionals who personally deliver those services.
"Many people derive personal satisfaction from doing a job well, whether the job is, e.g., painting a house or performing open-heart surgery, and they strive to deliver a quality product, not in obedience to the superintending guidance of the administrative state, but because they want to."
Van Laningham is no stranger to controversial opinions. In 2014, he said a doctor accused of beating and handcuffing a patient during a yearlong sexual relationship should be allowed to continue practicing medicine.
Now, the cardiac doctors are considering whether to appeal the judge's decision.
In the meantime, they said they're relieved St. Mary's is no longer operating on children's hearts.
CNN's John Bonifield contributed to this report.